Monolithic additive manufacturing of fluid-structure coupled architected cellular mechanical system for rate-adaptive enhanced energy dissipation

Abstract

Passive damping systems that combine high dissipation capacity with rate-adaptive response and structural reusability remain challenging to realize using conventional single architected materials, which are typically governed by purely structural damping mechanisms, while conventional fluid dampers require complex assembly. Here, a novel viscous fluid-encapsulating cellular mechanical system (CMS) is realized as a complete damping device, in which energy dissipation is enhanced through orifice-governed viscous dissipation, activated by the coupling of compliant cellular deformation rather than material damage, while generating velocity-dependent hydraulic resistance.The architected CMS was fabricated as a single monolithic unit via single-step additive manufacturing without post-processing. The fluid-filled CMS was systematically investigated for quasi-static and dynamic testing, delivering substantially enhanced ED for filled CMS, 183.7% more at 1000 mm/min than empty, while both configurations exhibited near-identical values at quasi-static rates (328 vs 379 mJ at 10mm/min), confirming negligible hydraulic contribution below the threshold speed. Similarly, an exceptional improvement of 194% in loss factor was observed, while SED increased from 0.17 to 0.39 at maximum speed. Under dynamic loading conditions, the filled CMS exhibited pronounced optimal operating frequency-dependent behavior, with ED 162.8% higher than the empty one at 1Hz and moderating to 138.7% at 2.5 Hz. The design strategy opens a new avenue for additively manufactured lightweight adaptive cellular hydraulic damping devices, enabling proportional scaling with lattice size, for a diverse range of energy dissipation applications.